Steering construction for tractor units



July 18, 1933.

C. RORABECK STEERING CONSTRUCTION FOR TRACTOR NITS Filed May 7, 1931 4 Sheets-Sheet' 1 July 18, 1933. c. RoRABEcK STEERING CONSTRUCTION FOR TRACTOR'UNITS 4 Sheets-Sheet 2 Filed May '7, 1931 NWN m@ UE m l u A l i m July 18, 1933.

RoRABEcK 1,918,564 STEERING CONSTRUCTION FOR TRACTOR UNITS Filed May '7, 1931 4 Sheets-Sheet V3 July 18, 1933. QRORABECK STEERING CONSTRUCTION FOR TRACTOR UNITS Filed May '7, 19:51 4 sheets-sheet 4 C' era/ec:

yox n MMG@ 219i Patented July 18; 1.9133v n stamm`'Iuiraejncx.` or cHIoeo ,IIEIGH'Is ILLINOIS ppiigtmf mea may 7,

This invention 'relates' toimprovements in steering mechanism for the tractor units of power shovels for excavators or heavy Ina-VV y chinery. It vis common d f excavator by tractor units at the four corners` inorder to render the movement of the excarelatively more'V JQeaSy. Fiach of thetractor` units generallycomprise four supporting 'wheels engaging a pair ofvilexible tractor chains formed by.` inter-'connected tractor links which have a? vator from place to place flat bearing surface upon the ground.

Itis a purpose ofthe present inventionto' 1'5`7` provide a steeringframe which may be readily applied I e tor unit in order that the tractor unit may be rotated on a vertical ofsteering the excavator.

2U) l Itis further an object of theV inventionto` o attach a steeringfrarne to apair of tractor so that each' I unitsat one end'o anexcavator may be rotatedon a vertical axis and to profv vide' connecting mechanism between thepair;

n C of steering tractor units Y' 'so that Vboth may be turned-together for the purpose of steer,-l ling the excavator. '1

It is further a purposeof Y jvention toV provide improvements in various 'details of the steering construction toprovide simple mechanism that may be readily oper` ated under all conditions of use. f v

Furtherand additional eatureso the improvements kof 'the present invention will be Y tached drawings, in .which--` Figure 1 is a side elevation of the front-1 ofthe construction Figure 5 is a sideelevat'on of the steering.

arm; Figure A 6 is a detail plany view of the steering nut;

to the standard rame'of thetracaxisfor the purpose'- the 'present in-` f more readily apparent from the' followingdescription taken in connection with the. at

1931.' serial N'pfsa'aeca 'i o' v e i Fgure'fisan end viev'v-of thednut shown;v

ing parts` shown in FigureQ,"and` "ing parts shownin Figures 9 and 10.V

rotatableV frame' 14 of a tractor?V unit' which has suitable wheels tractor chains 118.

i into a steering unit.

l- I shovv1'i-njFigi1re4 part-s which. may bel attached'to `the vtractor frame in order'topermit steering ofthe unitH f Figure is a vertical'section taken' through .la Y the'attachment of the steering arm to thef practiceto supporta heavy In thef drawings 10 indicates the frame of i the excavator, or-lpower shovel whichis pro-V vided at each of its four 'corners' with abearo,

ing `12 for supporting the excavator upon, af

tgp view of thefzhosingf i n parts whicharevcarried'by thesteering -n1'1't;"

(fFigure l0 isa front elevation of the hou's-f-jo 16 engaging the endless '5" Ordinarily` vthe tractor `units are;l non-rotatable on' averticalgaxis withrespectto the frameof the excavator butf 5 according vto` my invention l av -mechanisrn is disclosed for readily converting a tractor un itj'y n demas of fhiframing' e if p *through a' steering arm."V Thus Ifvshow" lower 4frame part I9 which has at one end a :i l pair of pintle-receivingbearings 207-20'1 adapted to be connected byja pintle 22toV av steering arm 24. f rllhe pinconnecticn22de i n therefore on'a horizontal axis and lperrni'cs rrelativemovement between' the steering"ar1n"'85; Y v i heights and movement of the tractorjunit.` .l

The lowerlfra'me part `l9has curvediianges f `S26 at each end which engagewith thefframe of theftractor unit andcooperate with 'thecurved'flanges 28 formed yon apaiij offcap,y

membersBQfwhich maybe suitably secured to the castnglby bolts'lass'hownjin Figwk l therefore, be attached tothe frame of the openings, Y through openings align Y thecap members 34 in the, Part19 which are ed `with bolt-receiving 'openings in d 30. ,-ThepmembershaveI l l sa Y in Figure 5,

clamped together at a median plane, as indi-v cated in Figures 8, y9.and10. Theparts 44 are providedl Withlongitudinal bolt-'receiving openings 46`i'vhich may receiveclamping bolts.v Each of the .parts 44 hasa bearing 48 to rotatably Vsupport the steering Worm 50 Which has a pair of cylindrical projections 52 adapted tofit into the bearings 48of the housing parts44. The side Walls of the slots I 42 are divergently inclined, as indicated at 54' in Figure 9, from the median clamping plane` betWeen 'theparts towards the ends thereof' to accommodatetheangulai'ity ofthe steering arm With respect to the v'steering Worin.v

:The steering Worm 5() has an internal spiral thread 56 for engaging the threaded steering shaft 58 supported by bearings 60 and@ on the fran-ie 10 ofthe-excavatoix i vvTurning ofthe Wheel 64 Will rotate the steer- Y ing shaft 58 and causethe Worm 50 to travel;

, The steeringshaft may beoperatedby a Asteering Wheel 64 and, as shown, the shaft 58 may connect to an extension shaft 66 extending across the frame l0 for steering the/trac- Ltor unit on the other Vside of the excavator.

` The operation'vvill be readily apparent:

inf an axial direction. The travelV of the 4son of the Worin Will cause the-steering arm 24'v to swing and rotate the tractor unit about its verticallaxis, due to the universal connection'of the By reapivotalsupport of the housing,"

steering arm to thel steering Worm.

which slidably engages -the steering arm,

vrelative movement ofL the parts-.is taken care of. Furthermore, due to the pivotal connection of the steering arm to the steering frame any differences in the relative height between the tractor unit and the steering shaft Will rnot require any change inthe parts.

It Will'be obvious that lmany lchanges and modifications may be resorted to Without departing from the spirit of inyinvention as expressed in the appendedclainis.

Ifclaini: "1. In an excavator, a tractor unit support-Y ing' one cornerof the frame of theexcavatorA and pivoted on a vertical axis, a steering frame secured to the tractor unit, a steering y arm pivotallycoiinected on a horizontal` axis to oneendof said steering fraine,'a threaded rotatable steering shaft carriedbythe frame ofvsaid excavator, a steering Wheel for kturning said.steeringshaft,V a Worm mounted to Y The upper andlower,

travel axially on said steeringk shaft, a housing pivotally mounted by said steering Worin on an axis transverse to said steering shaft and said steering arm having a fork-shaped end for slidably receiving'said housingand permitting angular movement of said steering arm With respect to said 'steeringshaft 2. In an excavator a tractor unit 'su aorting one corner of said excavator pivoted on a vertical* axis, asteering arm pivotally'connected on.ahoriZontal kaxis With said tractor unit, a steering shaft'rotatably supported on.

said excavator,"asteering Worin threaded to Vsaid steering shaft and adapted to travel `".axially upon rotation of (said steering shaft,

a. housing pivotally Vsupported by 'said steering Worm on anaxis transverse tosaid steering shaft, said Vsteering armhaving a forkl shaped end slidably receiving said housing With provision for .permitting angular move ment relative thereto.

i 3. In an excavator,a main frame,a tractoil unit frame, a pair -of-endlessitractor chains carried by connecting the tractor unit frame tractor unit frame, means 'i With the main frame for movement about a substani.2r

tially vertical axis` for steering, a steering frame secured to lthe tractor' unit frame, ay

steeriiigarin pivotedfat its inner end to 'said steering. frame on ya substantially horizontal.` axis, a rotatable steering shaftsupported by j substantially'vr horizontal, a steering Worin threaded tofsaidf said mainframe With its axis steering shaft andadapted vto travel. axially of said shaft upon rotation tliereof ,a housing enclosingfsaid Wormlandpivotedthereto on an axistransverse to the axisofsaidsteer-` f ing shaft and. a slidable joint between the.; outerend of said steeringarm andsaid housfr ing, wherebyrotation of said steeringshafty Will turn said-tractor unit@ frame'about its 1 n.

substantiallyA vertical axis.

vet.' In a vehicle, a'tractorunit support-forsaid vehicle, va st eeringframe secured to the tractor u nit, ajsteering arm extending from said steering frame Vin ajdirection paralleli' to the direction y and havingits inner end pivoted thereto onga yhorizontal axis extending substantially trans.- verse to said directionof travel, a rotatable 'steering shaft carried by the vehicle in an approximately horizontal position, univers v sal joint connection bet'vveenthe outer end of said steeringL arm and said steeringlsliaft, and

means for imparting lateral movement from` i of travelfofthe tractor unitjiio said steering shaft to said steering arm upon I rotation thereof, said last-namedineans com- V on the ysteering shaft and-a Worin coacting With said threaded" prising a threaded portion portionv andrairying said universalvljoint connection.

';l i i CLAUDE RoniiBEcxff" 

